Considerable research has been carried out to establish a rational assessment method for nuclear power plants against local damage caused by an accidental projectile impact. Most of the empirical formulas that have been proposed seek to quantitatively investigate local damage to reinforced concrete (RC) structures caused by a rigid projectile impact. These formulas have been derived based on impact tests performed perpendicular to the target structure, while only a few impact tests oblique to the target structure have been studied. This study aims to propose a new formula for evaluating local damage to RC structures caused by oblique impact based on experimental and simulation results. At present, we have validated an analytical method via comparison with experimental results and have conducted simulation analyses of oblique impact assessments on RC slabs using various projectiles with flat nose shapes. In this study, the same analytical method will be used to investigate perforation damage to RC slabs subjected to oblique impact by projectiles with hemispherical nose shapes. In this paper, the effects of projectiles’ nose shapes on perforation damage to RC slabs, the residual velocity of projectiles and the time history of energy transmission will be discussed.